Combinations

What you'll learn

1. Explain why combinations count fewer arrangements than permutations for the same n and r
2. Apply the combination formula C(n,r) = n!/(r!(n-r)!) to count the number of ways to choose r items from n items when order does not matter
3. Determine whether a problem requires permutations or combinations by asking "does order matter?"
4. Solve applied problems involving combinations (committees, teams, selections, hands of cards)

Prerequisites

• Permutations